STS-130: Endeavour docks with ISS – Port Wing protrusion evaluated

by Chris Bergin

An upper elevon “sliding seal” on one of Endeavour’s port wing flippers has protruded, although early Damage Assessment Team (DAT) reports claim only a low level of concern. As STS-130 moved through Flight Day 3, Endeavour and her External Tank appear to have enjoyed an extremely clean ascent, as the orbiter and her crew docking with the International Space Station (ISS).

STS-130 Latest:

Endeavour is proceeding through the mission timeline as planned, with Flight Day 3’s R-bar Pitch Maneuver (RPM) and docking now completed by the crew.

Flight Day 2 involved the opening inspections of Endeavour’s Thermal Protection System (TPS) via the Orbiter Boom Sensor System (OBSS). The data is currently being evaluated by the DAT engineers on the ground.

“Flight day 2 Activities Completed: Crew wake-up at 1810 EST last night. TPS and OMS pod survey with OBSS complete. EMU (EVA Suit) checkout and Centerline camera installation complete. ODS (Orbiter Docking System) ring extension and Rendezvous tools checkout complete,” noted the NASA Test Director Summary (L2).

“Flight Day 3 Activities Planned: Crew wake-up will be at 1714 EST this evening. Rendezvous with ISS. Pitch maneuvering for TPS photography. Dock with ISS Harmony mating Adapter-2. Hatch open and Welcoming.”

Later in Flight Day 3, the Space Station Remote Manipulator System (SSRMS) Canadarm2 will grapple the OBSS and handoff to Shuttle Robotic Arm (SRMS), as preparations are made to remove the newest addition to the ISS – Node 3 and Cupola – from the payload bay.

STS-130 Specific Articles:

Only a handful of technical issues are under evaluation – none of which are deemed as MER (Mission Evaluation Room) level concerns. The issues are all classed as “funnies” – which is MER-talk for minor.

“MER Items: None. Funnies: SRMS Voltage BITE; Occurred during checkout and was seen during STS-127 and it is known as a nuisance alarm,” noted the latest Mission Management Team (MMT) presentation (L2).

“Left OMS GN2 Pressure decay; Decay in this system has been seen on multiple flights. APU (Auxiliary Power Unit) 3 Drain Line Heater Higher set point; This has been seen on the previous three OV-105 (Endeavour) flights. HDTV downlink not successful.

The final item was spotted early today, relating to the protrusion from the Port Wing Elevon Cove – noted initially as an “anomalous object.”

The DAT presentation on the initial TPS findings concentrated on this area in their opening report, and currently have only a “low level” of concern for this issue being a problem for re-entry. More data will also be gathered via FD3’s RPM.

“Upper surface scans and imagery reviewed – no tile, FI blanket or gap fillers identified for assessment. Complete coverage of both OMS pods and both T0 areas. Vertical tail and forward fuselage complete,” noted the opening assessment from the DAT engineers, pointing to a very clean orbiter.

“Starboard WLE (Wing Leading Edge) carrier panels – full coverage on lower, partial coverage on upper 2-4. Port WLE carrier panels – full coverage on upper, partial coverage on lower 7-11. Areas with partial coverage will be imaged during RPM.

“Upper elevon sliding seal by flipper doors 12 and 13 identified as protruding approximately 3.8 inches.”

The seal that has protruded is made from sheet metal – inconel – and is spring loaded between the panels. The leading edge rides under the wing trailing edge and appears to have slipped out from under the wing side.

This upper trailing edge of the wing doesn’t experience the extremely high temperatures of reentry and thus should not be a major concern for reentry – as noted by the opening DAT findings.

“Photo shows edge of seal installed under the wing trailing edge as designed. Seal is intended to control venting. Low level of concern within TPS community,” noted DAT, before listing their forward plan, which includes checking closeout images from Endeavour’s STS-130 flow in her Orbiter Processing Facility (OPF).

“Forward work: Assessing Venting environments. Elevon positioning schedule during ascent and entry. Previous flight processing history. Pad & Access imagery after final Elevon cycling. Assessing subsystems under the Flipper Door.”

DAT have also reviewed both the ET Umbilical Well and Handheld Photography of STS-130’s External Tank post-separation (full sets in hi res on L2) – imagery that has shown a very clean tank, with only a few areas of foam loss.

Most notably, the intertank area of ET-134 has only lost a few areas of foam TPS – far less than seen on the previous few flights.

As with STS-129, the main area of intertank foam loss is on the -Z side of the tank, which holds little to no threat to the orbiter during ascent – given it is located on the “back” side of the ET.

Images also show around three of foam loss in front of the bipod, and one area of liberation on the edge of the SRB (Solid Rocket Booster) thrust panel. There are no obvious foam losses from any of the LH2 or LOX (LO2) Ice Frost Ramps (IFRs) – which have been the focus of mitigation efforts over recent years.

Meanwhile, back on Earth, the two SRBs are in the process of being returned to dock for their post flight evaluations. Their initial findings – per the MMT ascent report (L2) – noted the boosters performed as planned, as did all of the shuttle hardware during ascent.

“Retrieval Status: Boosters have been recovered and ships are underway back to port. Freedom and Liberty Star are expected at the dock tomorrow at 0800 and 1000 EST respectively,” added the NTD.

“Open Assessment is expected to begin on Thursday at 0700 EST,” which should result in the onboard video of the SRB’s ride during first stage and splashdown will be available by the weekend.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4500 gbs in size

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